Setting up the VPN - client

If you don't have the tool pty-redir on your host, you have to download the appropriate source package first:

Table 9.1: Source package, size and URL for pty-redir.

Package	Size	License	URL
pty-redir-0.1	20 KB	GPLv2	http://uncensored.citadel.org/pub/unix/pty-redir-0.1.tar.gz

Now, we're ready to compile pty-redir (assuming your pwd points to $\sim$/Dreamcast/SRC):

$ cd ../BUILD
$ tar -xvzf ../SRC/pty-redir-0.1.tar.gz -C .
$ cd pty-redir-0.1
$ make clean
$ make

Now, copy the binary to /usr/sbin:

$ su -c "cp pty-redir /usr/sbin"
$ cd ../..

Now, you're able to build a point-to-point encrypted tunnel with pppd over SSH with your identity - file:

$ /usr/sbin/pty-redir /usr/bin/ssh -t -e none -1 \
  -o 'Batchmode yes' -c blowfish -i ./identity \
  -l Tux 192.168.1.1 > /tmp/vpn-tunnel
$ sleep 5
$ /usr/sbin/pppd `cat /tmp/vpn-tunnel` \
  192.168.2.10:192.168.3.10

The IP - addresses used above are only an example for testing the tunnel. Normally, you've to check for a unused IP address of LAN 1 and one in LAN 2 between you can establish the encrypted SSH tunnel.

For testing purposes, you may ping the SEGA Dreamcast with the given IP address:

$ ping 192.168.3.10
PING 192.168.3.10 (192.168.3.10): 56 data bytes
64 bytes from 192.168.3.10: icmp_seq=0 ttl=255 time=6.4 ms
64 bytes from 192.168.3.10: icmp_seq=1 ttl=255 time=5.2 ms
64 bytes from 192.168.3.10: icmp_seq=2 ttl=255 time=4.5 ms
...

All sent packets go through the ppp? device of your host to the SSH tunnel, where they'll be encrypted. Then, these encrypted packets are sent over the SSH connection to the other point, where the process is invoked vice versa: A received packet will be decrypted and sent to ppp?.